Sorry, I probably should have said that I actually think I successfully remembered to switch off VPN before logging on to my Schwab account during the past month or so.
I went multiple years without having to do two-factor verification. I was so liberated from it that I evidently failed to realize that Schwab nixed email as a method of verification about 2 years ago.
Recently, I started using VPN, and all of a sudden I have to verify twice in one month. It seems odd to me, and leads me to somewhat suspect that VPN is the factor.
I have a US number attached to my Schwab account. That number is no longer active. I haven't been to the US in a long time.